Most conventional shoes present severe limitations as to the type and extent of orthopedic corrective devices or `orthotics` that can be inserted therein, particularly in the forepart, where the insertion of any extra material would affect the fit of the shoe in the usually fixed girth region adjacent the ball, waist, and instep of the foot as well as forwards thereof.
A few extra depth shoes are available in which orthotic devices may extend the full length of the shoe, notably those of P. W. Minor & Sons, Inc. of Batavia, N.Y. However, such shoes have found very limited acceptance. Orthotic inserts or `orthotics` for use therein are usually designed to correct for pronation or supination of the foot, (i.e. arch considerations), as well as for metatarsal problems, as such they are necessarily limited in thickness to permit the upper to properly fit the forepart of the foot. Also most patients in need of such orthotics insist on being able to use them in their own choice of the widest possible choice of shoe styles. This choice is usually limited by the need for girth adjustment to compensate for the extra volume taken up by the orthotic inserts. This leads to laced shoe styles becoming the preferred choice for such applications. Further limitations orthopedic in nature are presented by the fact that lacing and similar conventional girth adjustment arrangements are rarely useful in the continually flexing ball areas of the foot, for reasons of comfort as well as appearance. Thus the vast majority of orthotic inserts extend only from the heel to the waist area of the shoe (roughly at the midportion thereof) where laces can adjust the shoe girth to accommodate the added volume of the inserts. While such a system can provide proper corrected support to the foot and shoe while the wearer is standing, the available correction decreases to zero during the stride cycle when the weight is transferred to the ball and toes of the foot and therefore off the backpart corrective insert. Thus prior systems afford essentially no corrective support during this most important part of the stride cycle.
In other cases where orthotics are used, particularly when they are used as `lifts` to compensate for the difference between the length of a patient's legs, such corrections when confined to areas rearward of the ball are only compromise solutions. They afford proper lifting of the short leg while standing, but again offer no consistent and continual correction during the stride cycle because the short leg is provided with no correction when the wearer's weight is fully supported by the ball of the foot. This causes an imbalance in motion, which results in a gimp or uneven stride. This imbalance, depending on its extent, can cause lasting orthopedic damage to parts of the body, including knees, hips, spine, shoulders, and even jaw alignment and function.
Currently, the only orthopedically acceptable solution that is not an improper compromise is to increase the thickness of the entire shoe bottom of the shoe on the `short leg` foot to provide a completely symmetrical stance. However, many patients stubbornly resist this solution since it renders obvious their infirmity. To avoid being considered somewhat crippled, patients often try to control their stride and thus hide the infirmity, particularly when they think they are being observed, with such stride control often causing damage to knee and/or hip joints.
Another example of problems arising from shoe inserts capable of orthopedically improper use is described in U.S. Pat. No. 3,442,031 in which insole shims inserted in shoes for inside girth adjustment not only alter the designed tread of the shoes, but also cause the balls of the wearer's feet to be at different walking heights from the ground whenever the two feet are of differing girths, as is usually the case.
Another example of inserts adversely effecting the fit of conventional shoes is that of the `air pumping` insoles described in U.S. Pat. Nos. 4,062,131 and 3,256,621. To date, such insoles have been effective mainly for promotional purposes, as neither functions adequately when used as shown in the disclosures. To function properly with provision for an adequate volume of air transport, the shoe of U.S. Pat. No. 4,062,131 would need thicker resiliently compressible insoles than would be practical in conventional shoe constructions. Such thicker insoles under compression would cause the upper to become too loose to fit properly, causing attendent unsightly and uncomfortable upper buckling and backpart slippage during the stride cycle. U.S. Pat. No. 3,256,621 discloses a thicker sock, which is impractical for the same reasons discussed above. It also provides for openings in the midsole which area is supposed to assist in ventilating the shoe. Such openings are impractical since they permit water and dirt to easily enter the shoe. Moreover, most shoes are sufficiently loose on the foot to allow relatively free transport of air between the upper portions of the shoe and the foot therein, the areas where such ventilating air transport should properly occur, rather than through the edges of the midsole as described in the patent.
Among the objects of the present invention is to provide practical means to solve the aforementioned problems, including means for insertion of orthotic devices including full length orthotics into shoes without adversely affecting the fit of the shoe on the foot thereby, to allow proper orthopedic support correction throughout the stride cycle of the wearer, and to also allow such correction to be applicable to the widest possible variety of shoe styles, including those with no conventional girth adjustment means, such as loafer and other casual styles, boots, women's dress pumps, etc.
Another object of this invention is to provide means whereby such orthotics can compensate for differences between the length of the legs of the wearer not only while standing but during the stride cycle as well.
Still another object of this invention is to provide a means whereby foot support shims, in the form of insole elements substantially each of uniform thickness, can be used to adjust the girth of a shoe to that of a foot inserted therein and/or compensate for moderate leg length discrepancies of a wearer without adversely affecting either the fit of the shoe or the horizontal balance of the wearer's pelvis.
For a fuller understanding of the nature of these and other objects of this invention, reference should be made to the following detailed description taken in connection with the accompanying drawings.